On Thu, Sep 19, 2019 at 05:03:24PM +0200, Thomas Gleixner wrote:
> To prepare for converting the exit to usermode code to the generic version,
> move the irqflags tracing into C code.
>
> Signed-off-by: Thomas Gleixner <t...@linutronix.de>
> ---
> arch/x86/entry/common.c | 10 ++++++++++
> arch/x86/entry/entry_32.S | 11 +----------
> arch/x86/entry/entry_64.S | 10 ++--------
> arch/x86/entry/entry_64_compat.S | 21 ---------------------
> 4 files changed, 13 insertions(+), 39 deletions(-)
>
> --- a/arch/x86/entry/common.c
> +++ b/arch/x86/entry/common.c
> @@ -102,6 +102,8 @@ static void exit_to_usermode_loop(struct
> struct thread_info *ti = current_thread_info();
> u32 cached_flags;
>
> + trace_hardirqs_off();
Bah.. so this gets called from:
- C code, with IRQs disabled
- entry_64.S:error_exit
- entry_32.S:resume_userspace
The first obviously doesn't need this annotation, but this patch doesn't
remove the TRACE_IRQS_OFF from entry_64.S and only the 32bit case is
changed.
Is that entry_64.S case an oversight, or do we need an extensive comment
on this one?
> addr_limit_user_check();
>
> lockdep_assert_irqs_disabled();
> @@ -137,6 +139,8 @@ static void exit_to_usermode_loop(struct
> user_enter_irqoff();
>
> mds_user_clear_cpu_buffers();
> +
/* Return to userspace (IRET) will re-enable interrupts */
> + trace_hardirqs_on();
> }
